Local area network of serial intelligent cells

ABSTRACT

A serial intelligent cell (SIC) and a connection topology for local area networks using Electrically-conducting media. A local area network can be configured from a plurality of SIC&#39;s interconnected so that all communications between two adjacent SIC&#39;s is both point-to-point and bidirectional. Each SIC can be connected to one or more other SIC&#39;s to allow redundant communication paths. Communications in different areas of a SIC network are independent of one another, so that, unlike current bus topology and star topology, there is no fundamental limit on the size or extent of a SIC network. Each SIC can optionally be connected to one or more data terminals, computers, telephones, sensors, actuators, etc., to facilitate interconnectivity among such devices. Networks according to the present invention can be configured for a variety of applications, including a local telephone system, remote computer bus extender, multiplexers, PABX/PBX functionality, security systems, and local broadcasting services. The network can use dedicated wiring, as well as existing wiring as the in-house telephone or electrical wiring.

This is a continuation of copending parent application Ser. No.10/178,223, filed Jun. 25, 2002, which itself is a continuation of U.S.patent application Ser. No. 09/123,486 filed Jul. 28, 1998, now U.S.Pat. No. 6,480,510, issued Nov. 12, 2002

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to local area networks and, moreparticularly, to local area network topologies based on serialintelligent cells.

Bus Topology

Most prior art local area networks (LAN) use a bus topology as shown byexample in FIG. 1. A communication medium 102 is based on two conductors(usually twisted pair or coaxial cable), to which data terminalequipment (DTE) units 104, 106, 108, 110, and 112 are connected, viarespective network adapters 114, 116, 118, 120, and 122. A networkadapter can be stand-alone or housed within the respective DTE.

This prior art bus topology suffers from the following drawbacks:

1. From the point of view of data communication, the medium can varysignificantly from one installation to another, and hence properadaptation to the medium cannot always be obtained.

2. The bus topology is not optimal for communication, and hence:

a) the maximum length of the medium is limited;

b) the maximum number of units which may be connected to the bus islimited;

c) complex circuitry is involved in the transceiver in the networkadapter;

d) the data rate is limited.

3. Terminators are usually required at the ends of the medium, thuscomplicating the installation.

4. Only one DTE can transmit at any given time on the bus, and all otherare restricted to be listeners.

5. Complex arbitration techniques are needed to determine which DTE isable to transmit on the bus.

6. In case of short circuit in the bus, the whole bus malfunctions, andit is hard to locate the short circuit.

7. Addresses should be associated independently with any networkadapter, and this is difficult to attain with bus topology.

Star Topology

A number of prior art network devices and interconnections summarizedbelow utilize star topology.

The multiplexer is a common item of equipment used in communication,both for local area networks and wide-area networks (WAN's). It is usedin order to provide access to a data communications backbone, or inorder to allow sharing of bandwidth between multiple stations. As shownin FIG. 2, one side of a multiplexer 202 is usually connected to asingle high data rate connection 204 (“highway”), but several suchconnections can also be used. The other side of multiplexer 202 hasmultiple low data rate connections 206, 208, 210, 212, and 214. Theellipsis . . . indicates that additional connections can be made. Eachlow data rate connection uses part of the bandwidth offered by the highdata rate connection. These low data rate connections can be of the sametype or different types, and can have different or identical data rates.The multiplexing technique most commonly used is time-domainmultiplexing (TDM). However, frequency-domain multiplexing (FDM) is alsoused.

A popular multiplexer in use is the voice multiplexer, shown in FIG. 3.A pulse-code modulation (PCM) bus 304 handling 2.048 megabits persecond, containing 30 channels of 64 kilobits per second is connected toone side of a PABX/PBX 302, and up to 30 telephone interfaces 308, 312,and 316 are connected to the other side via connections 306, 310, and314. The ellipsis . . . indicates that additional connections can bemade. In this configuration, each channel in the PCM bus can be switchedor be permanently dedicated to a specific telephone line. An example ofsuch system is disclosed in U.S. Pat. No. 3,924,077 to Blakeslee.

Similarly a small private branch exchange (PABX/PBX), as shown in FIG.4, is widely used (usually in an office or business environment) whereseveral outside lines 403, 404, and 405 are connected to one side of aPABX/PBX 402, and multiple telephones 408, 412, and 416 are connected tothe other side via lines 406, 410, and 414, respectively. The ellipsis .. . indicates that additional connections can be made. The PABX/PBXconnects an outside line to a requesting or requested telephone, andallows connection between telephones in the premises.

In the configurations described above, star topology is used in order toconnect to the units to the multiplexer, which functions as the networkhub. The disadvantages of star topology include the following:

1. A connection between each unit and the network hub is required, andthe wiring required for this connection can involve a lengthy run.

Thus, when adding new unit, an additional, possibly lengthy, connectionbetween the new unit and the network hub must be added.

2. No fault protection is provided: Any short circuit or open circuitwill disrupt service to the affected units.

3. The multiplexer can impose extensive space and power requirements.

Computer Interfaces

Various interface standards have been established in order to allowinteroperability between the PC (personal computer) or workstation andits various connected elements. These standards usually relate to bothmechanical and electrical interfaces, and include industry standardarchitecture (ISA), extended industry standard architecture (EISA),Personal Computer Memory Card Industry Association (PCMCIA), intelligentdrive electronics (IDE), small computer system interface (SCSI), andothers. Each added hardware unit usually utilizes a specific softwaredriver for interoperability with the specific platform. These protocolsare applicable to small distances only, and allow units to be housedwithin or nearby the PC or workstation enclosures. For example,equipping a PC for video capture could involve a plug-in ISA card housedwithin the PC on the motherboard, a video camera connected to the card,and a software driver. This configuration does not allow remote videomonitoring.

Relevant Prior Art

The use of the same wire pair or pairs for both power and datacommunication is well known, and is widely used in telecommunications,from “Plain Old Telephone Service” (“POTS”) to Integrated ServicesDigital Network (ISDN) and broadband services in the local-loopincluding other Digital Subscriber Line (xDSL) technologies. Such aconcept is described, for example, in U.S. Pat. No. 4,825,349 to Marcel,describing using two pairs for such a scheme. A DC-to-DC converter forsuch DC feeding is described, for example, in U.S. Pat. No. 4,507,721 toYamano et al.

The concept of power line communication (PLC) is also widely known.However, in most cases the connection is similar to a LAN environment,in which a single transmitter occupies the entire medium. Examples ofsuch techniques include X-10 and the consumer electronics bus (CEBus,described in the EIA-600 standard). Much of this technology uses complexspread-spectrum techniques in order to accommodate problematic media(characterized by high amounts of noise and interference). Even withsuch improved technologies, however, the data rate obtained isrelatively low.

Prior art in this field includes U.S. Pat. No. 5,684,826 to Ratner, U.S.Pat. No. 5,491,463 to Sargeant et al., U.S. Pat. No. 5,504,454 toDaggett et al., U.S. Pat. No. 5,351,272 to Abraham, U.S. Pat. No.5,404,127 to Lee et al., U.S. Pat. No. 5,065,133 to Howard, U.S. Pat.No. 5,581,801 to Spriester et al., U.S. Pat. No. 4,772,870 to Reyes, andU.S. Pat. No. 4,782,322 to Lechner et al. Other patents can be found inU.S. Class 340/310 (sub-classes A/R and others) and International ClassH04M 11/04.

The concept of using existing telephone wiring also for datacommunication is first disclosed in U.S. Pat. No. 5,010,399 to Goodmanet al., where video signals superimposed over the telephone signals areused. However, the scheme used is of the bus type and has the drawbacksof that topology. Similarly, the idea of data transmission over a publicswitched telephone network (PSTN) using the higher frequency band iswidely used in the xDSL systems, as is disclosed in U.S. Pat. No.5,247,347 to Litteral et al. The patent discloses an asymmetric digitalsubscriber line (ADSL) system. However, only a single point-to-pointtransmission is described over the local-loop, and existing in-housewiring is not discussed, and thus this prior art does not disclose howto configure a full multipoint network. Multiplexing xDSL data and thePOTS/ISDN data uses FDM principles, based on the fact that the POTS/ISDNservices occupy the lower portion of the spectrum, allowing for the xDSLsystem to use the higher bandwidth.

A home bus network using dedicated wiring is disclosed in U.S. Pat. No.4,896,349 to Kubo et al., and a home automation network based on a powerline controller (PLC) is disclosed in U.S. Pat. No. 5,579,221 to Mun.U.S. Pat. No. 4,714,912 to Roberts et al. is the first to suggestcommunicating data over power lines not in bus topology but as‘break-and-insert’. However, only single conductor is used, and thereceivers are all connected again using a bus topology.

In addition, U.S. patent application Ser. No. 08/734,921, Israel PatentApplication No. 119454, and PCT Patent Application No. PCT/IL97/00195 ofthe present inventor disclose a distributed serial control system ofline-powered modules in a network topology for sensing and control.These documents, however, do not disclose a local area network for datacommunications.

The prior art documents mentioned above are representative examples inthe field. Certain applications are covered by more than one issuedpatent.

There is thus a widely recognized need for, and it would be highlyadvantageous to have, a means of implementing a local area network fordata communications which does not suffer from the limitations inherentin the current methods. This goal is met by the present invention.

SUMMARY OF THE INVENTION

The present invention is of a local area network for data communication,sensing, and control based on serially connected modules referred to as“serial intelligent cells” (SIC's). An example of a local area networkof such devices according to the present invention is illustrated inFIG. 7, to which reference is now briefly made. In this example, SIC's700, 702, 704, 706, and 708 are connected by one or more conducting wirepairs (such as a twisted pair 710). This allows chaining, such as SIC700 to SIC 702 to SIC 704. However, SIC 700, SIC 706, and SIC 708,located at the ends are equipped with single connection. SIC 704 isequipped with three connections, and even more connections are possible.A SIC may be interfaced to one or more DTE's, as illustrated by a DTE714 interfaced to SIC 700 and by DTE's 716 and 718 interfaced to SIC704. SIC's need not have an interface, however, as is illustrated by SIC706 and SIC 702. SIC 702, though, serves as a repeater, connecting SIC700 and SIC 704. It is to be noted that the networks according to thepresent invention utilize electrically-conducting media to interconnectthe SIC's. Each electrically-conducting medium connects exactly twoSIC's into a communicating pair of SIC's which communicatebidirectionally and independently of other communicating pairs in thelocal area network. Electrically-conducting media are media whichtransmit signals by conducting electrical current or by propagatingelectrical potential from one point to another. Electrically-conductingmedia include, but are not limited to wires, twisted pair, and coaxialcable. But electrically-conducting media do not include media such asfiber optic lines, waveguides, microwave, radio, and infraredcommunication media.

As noted above, SIC's in a communicating pair communicatebidirectionally. For example, SIC 704 can initiate communication (as asender) to SIC 702 (as a receiver), but SIC 704 can just as wellinitiate simultaneous communication (as a sender) to SIC 700 (as areceiver). Bidirectional communication can take place simultaneously,and herein is taken to be equivalent to “full duplex” communication. Inaddition, as noted above, the communication between the SIC's of acommunicating pair is independent of the communication between the SIC'sof any other communicating pair, in that these communications neitherpreclude nor affect one another in any way. Furthermore, everycommunication between SIC's is a “point-to-point communication”, whichterm herein denotes a communication that takes place between exactly onesender and exactly one receiver. This is in contrast to a bus-basedcommunication, in which there are many (potential) receivers and many(potential) senders. Consequently, in the topology according to thepresent invention, there is automatically a termination in the physicallayer at each end of a connection (a SIC), both simplifying theinstallation and insuring more reliable communication.

The topology according to the present invention is superior to the priorart bus topology in the following ways:

1. There is no physical limit to the number of SIC's which may beinstalled in the network, and hence no physical limit to the number ofDTE's in the network.

2. Point-to-point communication allows higher data rates over greaterdistances.

3. Point-to-point communication requires less complex circuitry than buscircuitry.

4. Several SIC's can transmit and receive simultaneously. For example,SIC 700 can communicate with SIC 702 while SIC 704 communicatessimultaneously with SIC 706.

5. There is no need for arbitration, allowing more efficient utilizationof the network. Furthermore, priorities can be assigned to each SIC or,alternatively, to each specific message to allow the data routing totake care of priorities.

6. Addresses may be assigned by the network.

7. In the case of failure of any conductor or SIC, the network can sensethe fault immediately, and the specific location of the fault (up to thespecific SIC pair) is easily obtained.

Therefore, according to the present invention there is provided a localarea network for data communication, sensing, and control including aplurality of serial intelligent cells interconnected exclusively byelectrically-conducting media into at least one communicating pair,wherein: (a) each of the electrically-conducting media interconnects nomore than two of the serial intelligent cells; (b) each of thecommunicating pair includes one of the electrically-conducting media andexactly two of the serial intelligent cells; (c) each of thecommunicating pair engages in a communication exclusively over theelectrically-conducting media; and (d) each of the communicating pairengages in the communication bidirectionally and independently of thecommunication of any other of the communicating pair.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, withreference to the accompanying drawings, wherein:

FIG. 1 shows a common prior art LAN bus topology.

FIG. 2 shows a typical prior art multiplexer.

FIG. 3 shows a prior art voice multiplexer (star topology).

FIG. 4 shows a prior art voice exchange configuration (star topology).

FIG. 5 is a block diagram of a SIC for control applications according tothe present invention.

FIG. 6 is a block diagram of a SIC for data communications according tothe present invention.

FIG. 7 shows a LAN topology utilizing the devices of the presentinvention.

FIG. 8 shows an alternative LAN topology utilizing the devices of thepresent invention.

FIG. 9 shows a SIC-based multiplexer—PABX/PBX according to the presentinvention.

FIG. 10 shows a local area network according to the present inventionused as a computer bus extender.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The principles and operation of a local area network according to thepresent invention may be better understood with reference to thedrawings and the accompanying description.

FIG. 5 is a block diagram of a representative SIC 500 for use in controlapplications. A first line interface 502 is a first port for connectingto the previous SIC to receive incoming electrical power and local areanetwork data over electrically-conducting medium 503, which mayoptionally be connected to an electrical power main 501, so that SIC 500may be powered from electrical power main 501. Line interface 502 mayinclude the connector, fuse, lightning arrester and other protectionsuch as noise filters, etc. The incoming power/data signal is fed to afirst power/data splitter/combiner 504, which de-couples the (highfrequency alternating current) data signal from the power. Such apower/data splitter/combiner 504 (denoted for brevity in FIG. 5 as “P/Ds/c”) can be implemented by methods well-known in the art, such as usinga center-tap transformer, or alternatively with active components. Thedata signal is fed to a first modem 506 allowing bidirectionalcommunication, while the power is fed to a power supply 520. The abovescheme assumes that both power and data are carried by the same networkwires (line-powering). FIG. 5 illustrates the case where the SIC isline-powered by alternating current (for example, by the electricalpower main), in which case power/data splitter/combiner 504 is an ACpower/data splitter/combiner, which separates a low-frequencyalternating current power from the higher-frequency data signal.Otherwise, in the case where the SIC is line-powered by direct current,power/data splitter/combiner 504 is a DC power/data splitter/combiner,which separates direct current power from the data signal. In some casesthe line-powering method is not used. For example, power can be carriedby dedicated lines routed in conjunction with the data wiring.Alternatively, the SIC can be locally powered by a local power-supply.In both cases, the power/data splitter/combiner is not required, and thepower lines are directly connected to the SIC power-supply, while thedata connects directly to the modems. Parts of the SIC are shownoptionally housed within an electrical outlet 524, such that connectionsto the local area network as well as to the electrical power mains maybe made from electrical outlet 524. Electrical power from electricaloutlet 524 can be fed to an optional electrical appliance 525. Inaddition, SIC 500 contains an optional electrical power main feed 505which can also power electrical appliances or other devices.

Power-supply 520 provides the required voltages for the SIC and payloadoperation, and also outputs the power to a second Power/datasplitter/combiner 510, for coupling to the next SIC. Communication withthe next (fed) SIC is performed via a second modem 512 connected to asecond line interface 514 via power/data splitter/combiner 510, similarto power/data splitter/combiner 504 as previously described. Lineinterface 514 feeds to electrically-conducting medium 515, whichconnects to the next SIC. Modems 506 and 512 can be standard RS-485,RS-232, or any simple similar data interface transceiver. Alternatively,a complex transceiver can be used for achieving long ranges orhigh-speed operation. CPU and firmware contained in a control block 522control and monitor the unit operation and communication, as well ascontrol the payload through a payload interface 508 interfacing with apayload illustrated by a sensor/actuator 509. For example, interface 508can implement a 4-20 ma standard interface. In a similar way, SIC 500can be used for communication over the power line. To do this, payloadinterface 508 is replaced by a communication port and sensor/actuator509 will be replaced by a DTE.

A SIC for use in data communications as shown in FIG. 6 is substantiallysimilar to that used in control applications as shown in FIG. 5, but hassome specific differences as noted. Also illustrated in FIG. 6 is thecase where the local area network data is carried overelectrically-conducting media which are part of the telephone wiring ofa building. A SIC 600 has a first line interface 602 as a first port forconnecting to the previous SIC to receive incoming power, local areanetwork data, and telephony data via an electrically-conducting medium603. Line interface 602 may include the connector, fuse, lightningarrester and other protection such as noise filters, etc. The incomingpower/telephony/data signal is fed to a first telephony/datasplitter/combiner 604 (denoted for brevity in FIG. 6 as “T/D s/c”),which de-couples the local area network data from the power andtelephony data. Such a telephony/data splitter/combiner 604 can beimplemented by methods well-known in the art, such as using ahigh-pass/low pass filter, or alternatively with active components. Thelocal area network data signal is fed to a first modem 606 allowingbidirectional communication, while the power (DC) is fed to a powersupply 620, and the telephony data is fed to power/telephone interface624.

Power-supply 620 provides the required voltages for the SIC and payloadoperation, and also outputs the power to a second telephony/datasplitter/combiner 610, for coupling to the next SIC. Communication withthe next (fed) SIC is performed via a second modem 612 connected to asecond line interface 614 via telephony/data splitter/combiner 610,similar to telephony/data splitter/combiner 604 as previously described.Line interface 614 connects to an electrically-conducting medium 615,which connects to the next SIC. Modems 606 and 612 can be standardRS-485, RS-232 or any simple similar data interface transceiver.Alternatively, a complex transceiver can be used for achieving longranges or high-speed operation. CPU and firmware contained in a controlblock 622 control and monitor the unit operation and communication, aswell as control the payload through a payload interface 608 interfacingwith a payload 609, which may include sensors and actuators. Forexample, interface 608 can implement a 4-20 ma standard interface. SIC600 also includes an optional power/telephone interface 624, containedfor example in a telephone outlet 625, as well as one or morecommunications interfaces, such as a communication interface 626connected to a DTE 628.

In the case of DC line feeding, the power supply may be equipped with aline reversal function (for example, a diode-based bridge) in order toaccommodate a possible wire reversal.

Note that a SIC can be implemented as single device with all componentparts contained within one enclosure, but does not necessarily have tobe so implemented. In the case of a SIC used for data communications orcontrol applications, the hardware may be optionally divided between theSIC module and the DTE/Payload units. In the case of a SIC used fortelephone applications, the hardware may optionally be divided betweenthe SIC, the DTE payload unit, and the telephone outlet, such astelephone outlet 625, which allows connections to both telephoneservices (such as through a telephone 623) and the local area network(such through DTE 628). Telephone outlet 625 may be a wall outlet orjack. All or part of the SIC may be housed within a telephone outletsuch as telephone outlet 625, if desired. Furthermore, for SIC's usedonly as repeaters, a payload interface is not necessary.

Power/data splitter/combiner 510 (FIG. 5) can use various techniquesknown in the art. Coupling can be implemented, for example, as disclosedin U.S. Pat. No. 4,745,391 to Gajjar. Power-supply 520 (FIG. 5) can beconnected to the network using dedicated adapter or via specific SIC.The payload can also be connected using standard Ethernet or other LANinterface, hence emulating the network using the SIC's. Thisconfiguration makes use of standard interfaces, but operates at higherthroughput and data-rates than a conventional LAN.

SIC Addressing

A SIC can include an address. Addresses of SIC's on the network can beassigned via automatic assignment by the local area network itself byalgorithms known in the art, for example as disclosed in U.S. Pat. No.5,535,336 to Smith et al. Addresses can also be assigned via manualassignment, such as by the setting of mechanical switches on the SICunit. Addresses can also be determined by the DTE connected to the SIC,either by means of higher layers as done in most LAN systems, orphysically be means of the connection to the SIC (such as by addresslines).

SIC Powering

A SIC can receive electrical power locally, via a power source locatednear the SIC. However, one power source may be used to power some or allthe SIC's in the local area network using dedicated power lines. Theselines can be routed with the data communication wires. Alternatively,the same electrically-conducting media (the data communication wires)can be used to carry both electrical power and local area network datato the SIC's, by means of techniques well-known in the art, for exampleas in telephone systems. In such a case, a unit is required for couplingthe power supply to the local area network. This can make use of a SIC(such as SIC 706 in FIG. 7) or in a specific dedicated module. Sinceelectrical power is typically distributed at low frequencies (e.g., 60Hertz), whereas local area network data is typically at a much higherfrequency, electrical power can be combined with local area network datausing frequency-domain multiplexing. A SIC can therefore be powered fromthe electrical power mains, and can also deliver electrical power, asillustrated in FIG. 5 and detailed herein above.

The DTE's, sensors, and actuators connected to the SIC's can also belocally powered from the SIC's, or can use the same power resources viathe same channels as the SIC's. Part or all of a SIC can be housedwithin an electrical outlet so that the electrical outlet allowsconnection to the local area network as well as to electrical power.

Control

Although mainly intended to be used as communication network, the systemaccording to the present invention can also be used as a platform toimplement a sensing, control, and automation system. This is achieved byadding to one or more of the SIC's interfaces to sensors or actuators.The signals received by the sensors are transmitted over the network vialogic contained in the SIC's or in the DTE's, which thereupon operatethe relevant actuators. This automation function can be monitored by oneor more of the DTE'S.

The operation of the control may be associated with data communicatedover the network (for example, sensing the availability of power to aDTE) or may be independent of it, to allow control decisions to be madelocally.

DTE Interface

The DTE interface can be a proprietary interface or any standard serialor parallel interface, such as ITU-T V.35, ITU-T V.24, etc. In addition,a telephone interface (POTS) or ISDN may be used. This can suit intercomor PBX applications.

Fault Protection

The SIC topology described above can be modified to allow for singlefailure correction. In such a case, the SIC's are connected in a networkwith redundant paths, such as a circular topology as shown in FIG. 8. Inthis example, a SIC 800 is connected to a SIC 802, which is in turnconnected to a SIC 804, which is in turn connected to a SIC 806, whichis in turn connected to SIC 800. When connected in such configuration,any single failure in any conductor, such as in conductor pair 810, willnot effect the system operation, as data routing from any SIC to anyother SIC can be achieved via an alternate path. The term “circulartopology” herein denotes the topology of any local area network of SIC'saccording to the present invention which contains at least twocommunication paths between two different SIC's. For example, in FIG. 8,there are two communication paths from SIC 800 to SIC 804: onecommunication path is from SIC 800 to SIC 802 to SIC 804, and the otherpath is from SIC 800 to SIC 806 to SIC 804. Circular topology providesredundant communication paths that increase the immunity of the localarea network to communication faults. It should be noted that thecircular topology according to the present invention, as shown in FIG.8, differs significantly from the well-known “Token Ring topology” ofthe prior art, as discussed following.

Although circular topology as defined herein can be superficiallysimilar to the Token Ring topology, there are major differences betweenthem. One difference is in the data framing. The Token Ring uses thesame frame structure throughout all communication links in the network,and this requires that the same framing must be recognized by all thecells in the network. In the SIC network according to the presentinvention, however, each communication link (between any two connectedSIC's) is totally independent from all other network communication.Hence, a first SIC can communicate with a second SIC using one type offrame structure and protocol, while the same first SIC can communicatewith a third SIC using a different type of frame structure and protocol.

In addition, in a Token Ring network, there is single direction of dataflow at any given time from a single transmitter to one or morereceivers, and usually, the direction of data flow is constant. The SICnetwork according to the present invention, however, does not impose anylimitation on the data flow in any of the communication links. Fullduplex, half duplex or unidirectional communication is possible, and caneven vary from link to link throughout the network. This allows the SICnetwork to support two independent communication routes simultaneously,provided different segments are used. In FIG. 8, for example, SIC 800can communicate with SIC 802 while SIC 804 simultaneously communicatesdifferent data with SIC 806. This capability is not supported by any ofthe other network configurations.

The above differences affect, for example, the vulnerability of therespective networks to faults. In case of single break or short-circuitanywhere in the medium, the Token Ring network will collapse, disablingany further communication in the system. As another example, in thenetwork disclosed in U.S. Pat. No. 4,918,690 to Markkula et al.(hereinafter referred to as “Markkula”), this fault affects the physicallayer by disabling the media's signal-carrying capability. The TokenRing network will not function at all since the data layer functionalitybased on unidirectional transmission will not be supported. In contrast,however, a SIC network according to the present invention, will continueto function fully, except for the specific faulty link itself. All otherlinks continue to function normally. Furthermore, the ability tolocalize the fault is not easily performed either in a Token Ringnetwork or in the Markkula network. In the SIC network according to thepresent invention, however, it is simple and straightforward to tracethe fault to the affected link.

Data Distribution over Electrical Power Lines

An important configuration for a network according to the presentinvention uses the electrical power wiring of a building as acommunication media. This can be used, for example, to implement aninexpensive ‘home LAN’. Typical house mains have a connection to singlefeeder with numerous distribution points and outlets. The principlesaccording to the present invention specify a SIC to be located withineach outlet and at each distribution point. This will allow SIC-basedcommunications network, where communication takes place between eachpair of SIC's connected via the wiring. In such a case it is alsoexpected that the mains will also be used to power the SIC's. Aside fromusing the same wiring media, the electrical distribution and thecommunication system sharing the same mains can be totally decoupled.

Another configuration involves adding the SIC to the Mains wiring atpoints distinguished from the mains outlets. The preferred embodiment,however, consists of using the outlets points for both the electricalsupply and the DTE connection points. This involves replacing allelectrical outlets and distribution points with ‘smart’ outlets, havingboth electrical connections and a communications jack. In addition, suchunit may include visual indicators (e.g. LED's) to show thecommunication status, and may also include switches or other means todetermine the outlet address. Such a communication system could be usedfor applications associated with power distribution, as for example tocontrol the load connected to a specific outlet, for remote on/offoperation of appliances, timing of operations, delayed start,disconnection after pre-set time period, and so forth. Such acommunication system could also be used to monitor the power consumed byspecific outlets, such as for Demand Side Management (DSM) or AutomaticMeter Reading (AMR), allowing remote meter reading.

The above described topology may also apply to existing wiring. Onecommon example may be power wiring to consumers located in differentlocations. Such wiring typically relies on bus topology with taps. Inorder to use SIC technology, the wiring must be broken, and a SICinstalled between both ends.

In a similar manner, a communication network employing the electricalpower wiring of vehicles and vessel can be implemented, such as foraircraft, ships, trains, buses, automobiles, and so forth.

Implementing a Local Communication/Telephone System Using SIC's

In this application, existing telephone wiring (either POTS or ISDN) isused as the electrically-conducting media for the local area network,and is used for both local area network data communication and fortelephony. The term “telephony” herein denotes any telephone ortelephonic communication, including both including voice (POTS) and data(ISDN). Telephone outlets are usually connected in point-to-pointtopology without a distribution point. To set up a network, each outletis replaced with SIC-based outlet. If there are distribution points,these distribution points must also be SIC equipped. This configurationresults in a high-performance LAN between the telephone outlets. Asidefrom sharing the same media, the local area network can be decoupledfrom the telephone system. Alternatively, the local area network and thetelephone system can be combined, such that telephony is digitallyintegrated into the local area network data.

The outside telephone service can be treated according to one of thefollowing alternatives:

1. No telephone support. In this configuration, the connection to thenetwork (usually to the public network) is cut, and the network is fullyinternal, with no external telephone service.

2. Telephone as Payload. In this configuration, the telephone capabilityis retained, and telephony data may be integrated into the datacommunication of the local area network. One of the SIC's (usually theone closest to a public telephone network interface) or other dedicatedmodule interconnects (via the communication interface for example) tothe network interface (NI). This unit emulates a telephone interface tothe NI, so that public network operation is transparent and continues toperform as normal. However, the signals associated with the telephoneinterface, either the voice itself and the control/signaling (onhook/off hook, ringing, etc.) are digitized and transmitted in thenetwork as data stream, as part of the communication taking place in thenetwork. In the SIC's interfaced to telephones, these signals areconverted back to analog (or in any original form) and thus can be usedwith standard telephones. In this case, telephone functionality is fullyretained. However, failure in the communication network may result inloss of the telephone service. This can be improved by means of a systemwhich disconnects the SIC's circuitry and restores the original wiringrouting (this can be easily implemented by relays, which bypass theSIC's upon failure detection, manual intervention, or other relevantoccasion).

3. Communication over POTS or ISDN. In this method, theelectrically-conducting media interconnecting SIC's is the telephonewiring of a building. This method involves the known mechanism ‘POTSSplitting’, currently used in conjunction with xDSL technologies. Thisrequires a filter which separates the low-frequency portion of thespectrum (usually carrying the POTS associated signals and power) fromthe high-frequency portion of the spectrum (used for communication). Insuch an application, the AC/DC units in the SIC are replaced with suchPOTS splitter modules. The low-frequency band (POTS related) is passedtransparently (similar to the power pass), and branched to the telephonejack. The high-frequency band is used for the communication between theSIC's. This combining of high-frequency local area network communicationon the same electrically-conducting media with low-frequency telephonydata is a form of frequency-domain multiplexing.

In the latter two alternatives, each in-wall telephone outlet isreplaced with a SIC based outlet having both a telephone jack and one(or more) communication jacks.

Computer Bus Extender

The SIC network can be used as a computer bus extender, such as an ‘ISAbus extender’, as illustrated in FIG. 10. In this configuration, a SIC1006 is equipped with a computer bus connector 1004 which is connected,for example, to one of the ISA bus slots in a computer 1002, totransport data between the local area network and computer 1002. AnotherSIC 1010, remotely located, also has a computer bus connector 1012, suchas an ISA bus extender. This allows for a transparent ISA buscapability, where the ISA bus data will be transported in bothdirections over electrically-conducting medium 1008. The ellipses ( . .. ) indicate that additional SIC's and electrically-conducting media maybe present in the local area network between SIC 1006 and SIC 1010.Shown as an example, a video frame grabber card 1014 is plugged intocomputer bus connector 1012, and a video camera 1016 is connected tovideo frame grabber card 1014. Normally, video frame grabber card 1014is plugged directly into an ISA bus slot, such as in computer 1002.Here, however, the local area network acts as a bus extender so thatvideo frame grabber 1014 and video camera 1016 can be located remotelyfrom computer 1002. The normal software driver for the ISA bus slot incomputer 1002 can used, since computer 1002 is unaware of the fact thatonly ISA emulation is taking place. This way, the capability of havinggeneral remote PC components and peripherals can be easily achieved.This configuration features the above-described advantages, and thismethod can be used to attain various goals, such as fault protection.Similarly, this method can be used to connect several units remotely toa computer, using different ports in the computer.

Implementing Multiplexers and PABX/PBX Functionality

A network of SIC's may be used to implement a multiplexer or a PABX/PBXfunctionality, as illustrated in FIG. 9. In this example, a SIC 900 isconnected to a high data rate connection, such as PCM bus 916, while SIC902 and SIC 906 are connected to telephones 908, 910, and 912. SIC 904functions as a repeater in this example.

In this example, the local area network functions as a multiplexer,wherein the bandwidth of the high data rate connection (PCM bus 916) ismultiplexed through SIC 900 to SIC 902 and SIC 906, each of which mayuse a different portion of the bandwidth of the high data rateconnection (PCM bus 916). Moreover, by the addition of telephones 908,910, and 912, the local area network of FIG. 9 functions as a voicemultiplexer.

Other Applications of the Invention

A number of applications of the present invention have been discussedabove. Additional applications include, but are not limited to:intercom, PABX/PBX, security systems, video surveillance, entertainmentbroadcasting services, time (clock) distribution, and audio/video signaldistribution. The networks implemented by the present invention canextend locally within a single building or over a neighborhood.

While the invention has been described with respect to a limited numberof embodiments and applications, it will be appreciated that manyvariations, modifications and other applications of the invention may bemade.

1. A device for coupling to a data unit and to a wiring, said devicecomprising: a wiring connector operative for connecting said device tothe wiring; a first transceiver coupled to said wiring connector forconducting a full-duplex serial digital data communication over thewiring; a data interface connector connectable to the data unit; asecond transceiver coupled to said data interface connector forconducting a bi-directional serial digital data communication with thedata unit; firmware and a processor executing said firmware, saidprocessor being coupled at least to control said first and secondtransceivers; and a single enclosure housing said wiring connector, saidprocessor, said firmware, said data interface connector, and said firstand second transceivers, wherein said enclosure is attachable to a walland said device is addressable in a network.
 2. The device according toclaim 1, wherein: the wiring is at least in part in a wall of a buildingand is one of: a twisted-wire pair; a coaxial cable; a telephonewire-pair; and powerline wiring; said wiring connector is adapted toconnect to the wiring; and said first transceiver is operative forconducting the full-duplex serial digital data communication over thewiring.
 3. The device according to claim 2, wherein said singleenclosure is constructed to have at least one of the following: a formsubstantially similar to that of a standard outlet; wall mountingelements substantially similar to those of a standard wall outlet; ashape allowing direct mounting in an outlet receptacle or opening; and aform to at least in part substitute for a standard outlet.
 4. The deviceaccording to claim 2, wherein said device is pluggable into andattachable to an outlet.
 5. The device according to claim 1, whereinsaid single enclosure is structured to attach to a mating fixturesecured on the wall.
 6. The device according to claim 1, furthercomprising: at least one active unit; a power supply connected to saidat least one active unit for DC powering said at least one active unit,said power supply having a connection point for connecting to a powersource; and a visual indicator coupled to said power supply forindicating a status, wherein said power supply comprises an AC/DCconverter or a DC/DC converter.
 7. The device according to claim 6,further comprising a power connector connectable to the power source,and wherein said connection point is coupled to said power connector forsupplying power to said device from the power source.
 8. The deviceaccording to claim 6 wherein the wiring further simultaneously carries apower signal, and wherein said connection point is coupled to receivethe power signal and to supply the power signal to said device forpowering at least part of said device.
 9. The device according to claim6 further comprising a power connector coupled to said connection pointand connectable to a further device for DC powering the further device.10. The device according to claim 1, further comprising at least oneuser settable manual switch coupled to said processor and actuatable bya user for assigning a device parameter.
 11. The device according toclaim 10, wherein said at least one manual switch is used to manuallyassign an address to said device.
 12. The device according to claim 1,wherein said device has an address assigned automatically or by a dataunit connected to said device.
 13. The device according to claim 1,wherein said first transceiver is operative to perform bi-directionalcommunication with one or more identical transceivers connected to thewiring.
 14. The device according to claim 1, wherein said firsttransceiver is operative to perform full-duplex point-to-pointcommunication with only a single other transceiver over the wiring. 15.The device according to claim 1, wherein said second transceiver isoperative to perform bi-directional communication with one or moreidentical transceivers.
 16. The device according to claim 1, whereinsaid second transceiver is operative to perform full-duplexpoint-to-point communication with only a single other transceiver. 17.The device according to claim 1, wherein communication with the dataunit conforms to an Ethernet standard.
 18. The device according to claim1, wherein at least one parameter of said device is configurable by theconnected data unit.
 19. The device according to claim 1 furtheroperative to provide a standard computer bus interface, and furthercomprising a computer connector coupled to said first transceiver andmechanical means for connecting and attaching said device to a computerplug-in unit.
 20. The device according to claim 19, wherein saidstandard computer bus interface is one of: an ISA interface; a PCMCIAinterface; an IDE interface; and a SCSI interface.
 21. The deviceaccording to claim 1, further operative to couple an analog unit to saidprocessor, and wherein said device further comprises an analog connectorconnectable to the analog unit for coupling an analog signal to saidprocessor, and a converter coupled between said analog connector andsaid processor for converting between the analog and digital signals.22. The device according to claim 21, wherein the analog unit is ananalog actuator for creating a physical phenomenon, and said converteris a digital to analog converter.
 23. The device according to claim 21,wherein the analog unit is an analog sensor for sensing a physicalphenomenon, and said converter is an analog to digital converter. 24.The device according to claim 21, wherein the analog unit is one of anaudio unit and a video unit and the analog signal is one of an audiosignal and a video signal, respectively.
 25. The device according toclaim 21, wherein the analog unit is a telephone unit, said analogconnector is a telephone connector and the analog signal is a telephonesignal.
 26. The device according to claim 21, further comprising: atleast one active unit; a DC power supply connected to said at least oneactive unit for DC powering said at least one active unit, said powersupply having a connection point for connecting to a power source; avisual indicator coupled to said power supply for indicating a status,and wherein said power supply comprises an AC/DC converter or a DC/DCconverter, and said analog connector is coupled to said DC power supplyand is connectable to the analog unit for DC powering the analog unit.27. A device for coupling to first and second data units, said devicecomprising: a first data interface connector connectable to the firstdata unit; a first transceiver coupled to said first data interfaceconnector for conducting full-duplex serial digital data communicationwith the first data unit; a second data interface connector connectableto the second data unit; a second transceiver coupled to said seconddata interface connector for conducting full-duplex serial digital datacommunication with the second data unit; and a single enclosure housingsaid first and second data interface connectors, and said first andsecond transceivers, wherein said enclosure is attachable to a wall andsaid device is addressable in a network.
 28. The device according toclaim 27, wherein said single enclosure is constructed to have at leastone of the following: a form substantially similar to that of a standardoutlet; wall mounting elements substantially similar to those of astandard wall outlet; a shape allowing direct mounting in an outletreceptacle or opening; and a form to at least in part substitute for astandard outlet.
 29. The device according to claim 27, wherein saiddevice is pluggable into and attachable to an outlet.
 30. The deviceaccording to claim 27, wherein said single enclosure is structured toattach to a mating fixture secured on the wall.
 31. The device accordingto claim 27, further comprising: at least one active unit; a powersupply connected to said at least one active unit for DC powering saidat least one active unit, said power supply having a connection pointfor connecting to a power source; and a visual indicator coupled to saidpower supply for indicating a status, and wherein said power supplycomprises an AC/DC converter or a DC/DC converter.
 32. The deviceaccording to claim 31, further comprising a power connector connectableto the power source, and wherein said connection point is coupled tosaid power connector for supplying power to said device from the powersource.
 33. The device according to claim 27, wherein the communicationwith the first data unit is independent of the communication with thesecond data unit.
 34. The device according to claim 27 furthercomprising a power connector coupled to said connection point andconnectable to a device for DC powering the device.
 35. The deviceaccording to claim 27, further comprising a processor and at least oneuser settable manual switch coupled to said processor and actuatable bya user for assigning a device parameter.
 36. The device according toclaim 35, wherein said at least one manual switch is used to manuallyassign an address to said device.
 37. The device according to claim 27,wherein said device has an address assigned automatically or by a dataunit connected to said device.
 38. The device according to claim 27,wherein said first transceiver is operative to perform bi-directionalcommunication with one or more identical transceivers.
 39. The deviceaccording to claim 27, wherein said first transceiver is operative toperform full-duplex point-to-point communication with only a singlemating transceiver.
 40. The device according to claim 27, wherein saidsecond transceiver is operative to perform bi-directional communicationwith one or more identical transceivers.
 41. The device according toclaim 27, wherein said second transceiver is operative to performfull-duplex point-to-point communication with only a single matingtransceiver.
 42. The device according to claim 27, wherein thecommunication with each of the first and second data units conforms toan Ethernet protocol.
 43. The device according to claim 27, wherein atleast one parameter of the device is configurable by one of the firstand second data units when connected to a respective data interfaceconnector.
 44. The device according to claim 27 further operative toprovide a standard computer bus interface, and further comprising acomputer connector coupled to said first transceiver and mechanicalmeans for connecting and attaching said device to a computer plug-inunit.
 45. The device according to claim 44, wherein said standardcomputer bus interface is one of: an ISA interface; a PCMCIA interface;an IDE interface; and a SCSI interface.
 46. The device according toclaim 27, further operative to couple an analog unit to the first dataunit, and wherein said device further comprises an analog connectorconnectable to the analog unit for coupling an analog signal to thefirst data unit, and a converter coupled between said analog connectorand said first transceiver for converting between the analog and digitalsignals.
 47. The device according to claim 46, wherein the analog unitis an analog actuator for creating a physical phenomenon, and saidconverter is a digital to analog converter.
 48. The device according toclaim 46, wherein the analog unit is an analog sensor for sensing aphysical phenomenon, and said converter is an analog to digitalconverter.
 49. The device according to claim 46, wherein the analog unitis one of an audio unit and a video unit and the analog signal is one ofan audio signal and a video signal, respectively.
 50. The deviceaccording to claim 46, wherein the analog unit is a telephone unit, saidanalog connector is a telephone connector and the analog signal is atelephone signal.
 51. The device according to claim 46, furthercomprising: at least one active unit; a DC power supply connected tosaid at least one active unit for DC powering said at least one activeunit, said power supply having a connection point for connecting to apower source; and a visual indicator coupled to said power supply forindicating a status, wherein said power supply comprises an AC/DCconverter or a DC/DC converter, and said analog connector is coupled tosaid DC power supply and is connectable to the analog unit for DCpowering the analog unit.
 52. The device according to claim 27, furtheroperative to transparently pass data from the first data unit to thesecond data unit and wherein said first transceiver is coupled to saidsecond transceiver.
 53. A device for coupling an analog unit to a wiringcarrying serial digital data, the device comprising: a wiring connectoroperative for connecting said device to the wiring; a transceivercoupled to said wiring connector for conducting serial digital datacommunication over the wiring; an analog connector connectable to theanalog unit; a converter for converting between analog and digitalsignals coupled between said analog connector and said transceiver forcoupling the serial digital data to the analog unit; and a singleenclosure housing said transceiver, said converter, said wiringconnector and said analog connector, wherein said enclosure isattachable to a wall and said device is addressable in a network. 54.The device according to claim 53, wherein the wiring is in a wall of abuilding and is one of: a twisted-wire pair; a coaxial cable; atelephone wire pair; and powerline wiring, and wherein said wiringconnector is adapted to connect to the wiring and said transceiver isoperative to for conducting full-duplex serial digital datacommunication over the wiring.
 55. The device according to claim 54,wherein said single enclosure is constructed to have at least one of thefollowing: a form substantially similar to that of a standard outlet;wall mounting elements substantially similar to those of a standard walloutlet; a shape allowing direct mounting in an outlet receptacle oropening; and a form to at least in part substitute for a standardoutlet.
 56. The device according to claim 54, wherein said device ispluggable into and attachable to an outlet.
 57. The device according toclaim 53, wherein said single enclosure is structured to attach to amating fixture secured on the wall.
 58. The device according to claim53, further comprising at least one active unit, and wherein said devicefurther comprises: a power supply connected to said at least one activeunit for DC powering said at least one active unit, said power supplyhaving a connection point for connecting to a power source; and a visualindicator coupled to said power supply for indicating a status, andwherein said power supply comprises an AC/DC converter or a DC/DCconverter.
 59. The device according to claim 58 further comprising apower connector connectable to the power source, and wherein saidconnection point is coupled to said power connector for supplying powerto said device from the power source.
 60. The device according to claim58 wherein the wiring further simultaneously carries a power signal, andwherein said connection point is coupled to receive the power signal andto supply the power signal to said device for powering at least part ofsaid device.
 61. The device according to claim 58 further comprising apower connector coupled to said connection point and connectable to acomponent for DC powering the component.
 62. The device according toclaim 58 wherein the wiring further simultaneously carries a powersignal, and wherein said connection point is coupled to the wiring forsupplying power to said device from the power signal.
 63. The deviceaccording to claim 53, further comprising a processor and at least oneuser settable manual switch coupled to said processor, operative foruser assigning a device parameter.
 64. The device according to claim 63,wherein said at least one manual switch is used to manually assign anaddress to said device.
 65. The device according to claim 53, whereinsaid device has an address that is automatically assigned or assigned bya data unit connected to said device.
 66. The device according to claim53, wherein the analog unit is an analog actuator for creating aphysical phenomenon, and said converter is a digital to analogconverter.
 67. The device according to claim 53, wherein the analog unitis an analog sensor for sensing a physical phenomenon, and saidconverter is an analog to digital converter.
 68. The device according toclaim 53, wherein the analog unit is one of an audio unit and a videounit and the analog signal is one of an audio signal and a video signal,respectively.
 69. The device according to claim 53, wherein the analogunit is a telephone unit, the analog connector is a telephone connectorand the analog signal is a telephone signal.
 70. The device according toclaim 53, wherein said transceiver is operative to perform full-duplexcommunication.
 71. The device according to claim 53, wherein saidtransceiver is operative to bi-directionally communicate with one ormore identical transceivers over the wiring.
 72. The device according toclaim 53, wherein said transceiver is operative to bi-directionallypoint-to-point communicate with only a single mating transceiver overthe wiring.
 73. The device according to claim 53, wherein at least oneparameter of the device is configurable by a connected data unit. 74.The device according to claim 53 further operative to provide a standardcomputer bus interface, said device further comprising a computerconnector and mechanical means for connecting and attaching said deviceto a computer plug-in unit, said computer connector being coupled tosaid wiring connector.
 75. The device according to claim 74 wherein saidstandard computer bus interface is one of: an ISA interface; a PCMCIAinterface; an IDE interface; and a SCSI interface.
 76. The deviceaccording to claim 53 further comprising firmware and a processorexecuting said firmware, and wherein the serial digital data is coupledto said processor via said wiring connector.
 77. The device according toclaim 76, further comprising at least one user settable manual switchcoupled to said processor and actuatable by a user for assigning adevice parameter.
 78. The device according to claim 77, wherein said atleast one manual switch is used to manually assign an address to saiddevice.
 79. A device for coupling to wiring carrying serial digitaldata, said device comprising: a wiring connector operative forconnecting the device to said wiring; a first transceiver coupled tosaid wiring connector for conducting serial digital data communicationover the wiring; and a single enclosure housing said wiring connectorand said first transceiver, wherein said enclosure is attachable to awall and said device is addressable in a network.
 80. The deviceaccording to claim 79, wherein the wiring is in a wall of a building andis one of: a twisted-wire pair; a coaxial cable; a telephone wire pair;and powerline wiring, and wherein said wiring connector is adapted toconnect to the wiring and said first transceiver is operative forconducting full-duplex serial digital data communication over thewiring.
 81. The device according to claim 80, wherein said singleenclosure is constructed to have at least one of the following: a formsubstantially similar to that of a standard outlet; wall mountingelements substantially similar to those of a standard wall outlet; ashape allowing direct mounting in an outlet receptacle or opening; and aform to at least in part substitute for a standard outlet.
 82. Thedevice according to claim 79, wherein the device is pluggable into andattachable to an outlet.
 83. The device according to claim 79, whereinsaid single enclosure is structured to attach to a mating fixturesecured on the wall.
 84. The device according to claim 79, furthercomprising: at least one active unit; a power supply connected to saidat least one active unit for DC powering said at least one active unit,said power supply comprising an AC/DC converter or DC/DC converter and aconnection point for connecting to a power source; and a visualindicator coupled to said power supply for indicating a status.
 85. Thedevice according to claim 84 further comprising a power connectorconnectable to the power source, and wherein said connection point iscoupled to said power connector for supplying power to said device fromthe power source.
 86. The device according to claim 84 wherein thewiring further simultaneously carries a power signal, and wherein saidconnection point is coupled to receive the power signal and to supplythe power signal to said device for powering at least part of saiddevice.
 87. The device according to claim 84 further comprising a powerconnector coupled to said connection point and connectable to acomponent for DC powering the component.
 88. The device according toclaim 79 further comprising firmware and a processor executing saidfirmware, said processor being at least coupled to control said firsttransceiver.
 89. The device according to claim 88, further comprising atleast one user settable manual switch coupled to said processor andactuatable by a user for assigning a device parameter.
 90. The deviceaccording to claim 89, wherein said at least one manual switch is usedto manually assign an address to said device.
 91. The device accordingto claim 79, operative for coupling the serial digital data to an analogunit, said device further comprising: an analog connector connectable tothe analog unit; and a converter for converting between analog anddigital signals coupled between said analog connector and said firsttransceiver for coupling the serial digital data to the analog unit. 92.The device according to claim 91, wherein the analog unit is an analogactuator for creating a physical phenomenon, and said converter is adigital to analog converter.
 93. The device according to claim 91,wherein the analog unit is an analog sensor for sensing a physicalphenomenon, and said converter is an analog to digital converter. 94.The device according to claim 91, wherein the analog unit is one of anaudio unit and a video unit and the analog signal is one of an audiosignal and a video signal, respectively.
 95. The device according toclaim 91, wherein the analog unit is a telephone unit, the analogconnector is a telephone connector and the analog signal is a telephonesignal.
 96. The device according to claim 79, wherein said firsttransceiver is operative to perform full-duplex communication.
 97. Thedevice according to claim 79, wherein said first transceiver isoperative to perform bi-directional communication with one or moreidentical transceivers over the wiring.
 98. The device according toclaim 79, wherein said first transceiver is operative to performbi-directional point-to-point communication with only a single matingtransceiver over the wiring.
 99. The device according to claim 79,wherein at least one parameter of the device is configurable by aconnected data unit.
 100. The device according to claim 79 furtheroperative to provide a standard computer bus interface, said devicefurther comprising a computer connector and mechanical means forconnecting and attaching said device to a computer plug-in unit, saidcomputer connector being coupled to said wiring connector.
 101. Thedevice according to claim 100, wherein said standard computer businterface is one of: an ISA interface; a PCMCIA interface; an IDEinterface; and a SCSI interface.
 102. A device for coupling an analogtelephone set to wiring carrying digitized telephone data, said devicecomprising: a wiring connector operative for connecting said device tothe wiring; a transceiver coupled to said wiring connector forconducting communication of the digitized telephone data over thewiring; a telephone connector connectable to an analog telephone set; aconverter for converting between analog and digitized telephone signalscoupled between said telephone connector and said transceiver forcoupling the analog telephone set to the digitized telephone data; and asingle enclosure housing said transceiver, said converter and saidwiring and telephone connectors, wherein said enclosure is attachable toa wall and said device is addressable in a network.
 103. The deviceaccording to claim 102, wherein the wiring is in a wall of a buildingand is one of: a twisted-wire pair; a coaxial cable; a telephone wirepair; and powerline wiring, and wherein said wiring connector is adaptedto connect to the wiring and said transceiver is operative forconducting full-duplex serial digital data communication over thein-wall wiring.
 104. The device according to claim 103, wherein saidsingle enclosure is constructed to have at least one of the following: aform substantially similar to that of a standard outlet; wall mountingelements substantially similar to those of a standard wall outlet; ashape allowing direct mounting in an outlet receptacle or opening; and aform to at least in part substitute for a standard outlet.
 105. Thedevice according to claim 103, wherein said device is pluggable into andattachable to an outlet.
 106. The device according to claim 102, whereinsaid single enclosure is structured to attach to attach to a matingfixture secured on the wall.
 107. The device according to claim 102,further comprising: at least one active unit; a power supply connectedto said at least one active unit for DC powering said at least oneactive unit, said power supply comprising an AC/DC converter or DC/DCconverter and having a connection point for connecting to a powersource; and a visual indicator coupled to said power supply forindicating a status.
 108. The device according to claim 107 furthercomprising a power connector connectable to the power source, andwherein said connection point is coupled to said power connector forsupplying power to said device from the power source.
 109. The deviceaccording to claim 107 wherein the wiring further simultaneously carriesa power signal, and wherein said connection point is coupled to receivethe power signal and to supply the power signal to said device forpowering at least part of said device.
 110. The device according toclaim 107 further comprising a power connector coupled to saidconnection point and connectable to a component for DC powering thecomponent.
 111. The device according to claim 102, wherein said devicehas an address assigned automatically or by a data unit connected tosaid device.
 112. The device according to claim 102, wherein saidtransceiver is operative to effect full-duplex communication.
 113. Thedevice according to claim 102, wherein said transceiver is operative toperform bi-directional communication with one or more identicaltransceivers over the wiring.
 114. The device according to claim 102,wherein said transceiver is operative to perform bi-directionalpoint-to-point communication with only a single mating transceiver overthe wiring.
 115. The device according to claim 102, wherein at least oneparameter of said device is configurable by a connected data unit. 116.The device according to claim 102 further operative to provide astandard computer bus interface, said device further comprising acomputer connector and mechanical means for connecting and attachingsaid device to a computer plug-in unit, said computer connector beingcoupled to said wiring connector.
 117. The device according to claim116, wherein said standard computer bus interface is one of: an ISAinterface; a PCMCIA interface; an IDE interface; and a SCSI interface.118. The device according to claim 102 further comprising firmware and aprocessor executing said firmware, wherein said processor is at leastcoupled to control said transceiver.
 119. The device according to claim118, further comprising at least one user settable manual switch coupledto said processor and actuatable by a user for assigning a deviceparameter.
 120. The device according to claim 119, wherein said at leastone manual switch is used to manually assign an address to said device.121. A device for parallel coupling to a wiring carrying bi-directionalserial digital data, said device comprising: a wiring connectoroperative for connecting said device to the wiring; a transceivercoupled to said wiring connector for conducting serial digital datacommunication over the wiring; a parallel port coupled to saidtransceiver for parallel coupling to the serial digital data; and asingle enclosure housing said transceiver, said parallel port and saidwiring connector, wherein said enclosure is attachable to a wall andsaid device is addressable in a network.
 122. The device according toclaim 121, wherein the wiring is in a wall of a building and is one of:a twisted-wire pair; a coaxial cable; a telephone wire pair; andpowerline wiring, and wherein said wiring connector is adapted toconnect to the wiring and said transceiver is operative for conductingfull-duplex serial digital data communication over the wiring.
 123. Thedevice according to claim 122, wherein said single enclosure isconstructed to have at least one of the following: a form substantiallysimilar to that of a standard outlet; wall mounting elementssubstantially similar to those of a standard wall outlet; a shapeallowing direct mounting in an outlet receptacle or opening; and. a formto at least in part substitute for a standard outlet.
 124. The deviceaccording to claim 122, wherein said device is pluggable into andattachable to an outlet.
 125. The device according to claim 121, whereinsaid single enclosure is structured to attach to a mating fixturesecured on the wall.
 126. The device according to claim 121, furthercomprising at least one active unit, and wherein the device furthercomprises a power supply connected to said at least one active unit forDC powering said at least one active unit, said power supply comprisingan AC/DC converter or DC/DC converter and having a connection point forconnecting to a power source, and visual indicator coupled to said powersupply for indicating a status.
 127. The device according to claim 126further comprising a power connector connectable to the power source,and wherein said connection point is coupled to said power connector forsupplying power to said device from the power source.
 128. The deviceaccording to claim 126 wherein the wiring further simultaneously carriesa power signal, and wherein said connection point is coupled to receivethe power signal and to supply the power signal to said device forpowering at least part of said device.
 129. The device according toclaim 126 further comprising a power connector coupled to saidconnection point and connectable to a device for DC powering saiddevice.
 130. The device according to claim 121, wherein said device hasan address assigned automatically or by a data unit connected to saiddevice.
 131. The device according to claim 121 further comprisingfirmware and a processor executing said firmware, wherein said processoris at least coupled to control said transceiver.
 132. The deviceaccording to claim 131, further comprising at least one user settablemanual switch coupled to said processor and actuatable by a user forassigning a device parameter.
 133. The device according to claim 132,wherein said at least one manual switch is used to manually assign anaddress to said device.
 134. The device according to claim 121 furtherwherein said parallel port is part of a standard computer bus interface,and said device further comprises a computer connector coupled to saidparallel port, and mechanical means for connecting and attaching saiddevice to a computer plug-in unit.
 135. The device according to claim134, wherein said standard computer bus interface is one of an ISAinterface and a PCMCIA interface.
 136. The device according to claim 121further comprising a data connector coupled to the said parallel portfor parallel bi-directional communication with a data unit.
 137. Thedevice according to claim 136, wherein the parallel communication isbased on an ITU-T V.35 standard.
 138. The device according to claim 121,wherein said transceiver is operative to perform full-duplexcommunication.
 139. The device according to claim 121, wherein saidtransceiver is operative to perform bi-directional communication withone or more identical transceivers over the wiring.
 140. The deviceaccording to claim 121, wherein said transceiver is operative to performbi-directional point-to-point communication with only a single matingtransceiver over the wiring.
 141. The device according to claim 121,wherein at least one parameter of said device is configurable by aconnected data unit.
 142. A device for coupling a data unit and ananalog unit to wiring that simultaneously carries a bi-directionalserial digital data signal multiplexed with an analog signal, the devicecomprising: a wiring connector operative for connecting said device tothe wiring; a data interface connector coupled to said wiring connectorand connectable to the data unit, for coupling the serial digital datasignal to the data unit; an analog connector coupled to said wiringconnector and connectable to the analog unit, for coupling the analogsignal to the analog unit; and a single enclosure housing said wiringconnector, said data interface connector and said analog connector,wherein said enclosure is attachable to a wall and said device isaddressable in a network.
 143. The device according to claim 142,wherein the wiring is in a wall of a building and is one of: atwisted-wire pair; a coaxial cable; a telephone wire pair; and powerlinewiring, and wherein said wiring connector is adapted to connect to thewiring.
 144. The device according to claim 143, wherein said singleenclosure is constructed to have at least one of the following: a formsubstantially similar to that of a standard outlet; wall mountingelements substantially similar to those of a standard wall outlet; ashape allowing direct mounting in an outlet receptacle or opening; and aform to at least in part substitute for a standard outlet.
 145. Thedevice according to claim 143, wherein said device is pluggable into andattachable to an outlet.
 146. The device according to claim 142, whereinsaid single enclosure is structured to attach to a mating fixturesecured on the wall.
 147. The device according to claim 142, furthercomprising at least one active unit, and wherein said device furthercomprises a power supply connected to said at least one active unit forDC powering said at least one active unit, said power supply comprisingan AC/DC converter or DC/DC converter and having a connection point forconnecting to a power source, and a visual indicator coupled to saidpower supply for indicating a status.
 148. The device according to claim147 further comprising a power connector connectable to the powersource, and wherein said connection point is coupled to said powerconnector for supplying power to said device from the power source. 149.The device according to claim 147 wherein the wiring furthersimultaneously carries a power signal, and said connection point iscoupled to receive the power signal and to supply the power signal tosaid device for powering at least part of said device.
 150. The deviceaccording to claim 147 further comprising a power connector coupled tosaid connection point and connectable to a component for DC powering thecomponent.
 151. The device according to claim 142, wherein said devicehas an address assigned automatically or by a data unit connected tosaid device.
 152. The device according to claim 142 further comprisingfirmware and a processor executing said firmware, wherein said processoris at least coupled to control at least one component of the device.153. The device according to claim 152, further comprising at least oneuser settable manual switch coupled to said processor and actuatable bya user for assigning a device parameter.
 154. The device according toclaim 153, wherein said at least one manual switch is used to manuallyassign an address to said device.
 155. The device according to claim152, wherein: the analog signal and the digital data signal arefrequency multiplexed on the wiring; the digital data signal is carriedin a frequency band distinct from, and higher than, the analog signal,and said device further comprises: a high pass filter coupled betweensaid wiring connector and said data interface connector for passing onlythe digital data signal; and a low pass filter coupled between saidwiring connector and said analog connector for passing only the analogsignal.
 156. The device according to claim 142, further comprising atransceiver coupled between said wiring connector and said standard datainterface connector, said transceiver being operative to effectfull-duplex serial digital data communication over the wiring.
 157. Thedevice according to claim 142, wherein said transceiver is operative tobi-directionally communicate with one or more identical transceiver overthe wiring.
 158. The device according to claim 142, wherein saidtransceiver is operative to bi-directionally communicate point-to-pointwith only a single mating transceiver over the wiring.
 159. The deviceaccording to claim 142, wherein the serial digital data signal coupledto the data unit conforms to an Ethernet protocol.
 160. The deviceaccording to claim 142, wherein at least one parameter if the device isconfigurable by a connected data unit.
 161. A device for couplingdistinct first and second data conveying transmission lines the firsttransmission line being at least in part in a wall of a building and thesecond digital data conveying transmission line being of a type distinctfrom the first digital data conveying transmission line, said devicecomprising: a first port couplable to the first data conveyingtransmission line; a first transceiver coupled to said first port forbi-directional serial digital data communication with a first furthertransceiver identical to said first transceiver over the first digitaldata conveying transmission line; a second port couplable to the seconddigital data conveying transmission line; a second transceiver coupledto said second port for bi-directional serial digital data communicationwith a second further transceiver identical to said second transceiverover the second digital data conveying transmission line, said secondtransceiver being of a type distinct from said first transceiver; and asingle enclosure housing said first and second ports and said first andsecond transceivers, wherein said first and second transceivers arecoupled to each other for passing data between said first and secondports, said enclosure is attachable to the wall, and said device isaddressable in a network.
 162. The device according to claim 161,wherein the first data conveying transmission line comprises at leasttwo conductors, said first port comprises a connector, and said firsttransceiver is operative for conducting signals over the at least twoconductors of the first data conveying transmission line.
 163. Thedevice according to claim 161, wherein at least one of the transmissionlines is one of: a twisted-wire pair; a coaxial cable; a telephonewire-pair; and powerline wiring, and wherein one of said ports is awiring connector that is adapted to connect to said at least one of thetransmission lines and said first transceiver is operative forconducting full-duplex serial digital data communication over said atleast one of the transmission lines.
 164. The device according to claim161, wherein said single enclosure is constructed to have at least oneof the following: a form substantially similar to that of a standardoutlet; wall mounting elements substantially similar to those of astandard wall outlet; a shape allowing direct mounting in an outletreceptacle or opening; and a form to at least in part substitute for astandard outlet.
 165. The device according to claim 161, wherein saiddevice is pluggable into and attachable to an outlet.
 166. The deviceaccording to claim 161, wherein said single enclosure is structured toattach to a mating fixture secured on the wall.
 167. The deviceaccording to claim 161, further comprising at least one active unit, andwherein said device further comprises a power supply connected to saidat least one active unit for DC powering said at least one active unit,said power supply comprising an AC/DC converter or DC/DC converter andhaving a connection point for connecting to a power source, and a visualindicator coupled to said power supply for indicating a status.
 168. Thedevice according to claim 167 further comprising a power connectorconnectable to the power source, and wherein said connection point iscoupled to said power connector for supplying power to said device fromthe power source.
 169. The device according to claim 167 wherein atleast one of the transmission lines further simultaneously carries apower signal, and wherein said connection point is coupled to receivethe power signal and to supply the power signal to said device forpowering at least part of said device.
 170. The device according toclaim 167 further comprising a power connector coupled to saidconnection point and connectable to a component for DC powering thecomponent.
 171. The device according to claim 161, wherein said devicehas an address assigned automatically or by a data unit connected tosaid device.
 172. The device according to claim 161 further comprisingfirmware and a processor executing said firmware, wherein said processoris at least coupled to control said first transceiver.
 173. The deviceaccording to claim 172, further comprising at least one user settablemanual switch coupled to said processor and actuatable by a user forassigning a device parameter.
 174. The device according to claim 173,wherein said at least one manual switch is used to manually assign anaddress to said device.
 175. The device according to claim 161, whereinthe first transmission line further carries a frequency multiplexedanalog telephone signal or AC power signal.
 176. The device according toclaim 161, wherein the second transmission line comprises at least twoconductors, said second port consists of a connector, and said secondtransceiver is operative for conducting signals over the at least twoconductors.
 177. The device according to claim 161, wherein the secondtransmission line in one of: a twisted wire pair; a coaxial cable; atelephone wire pair; and powerline wiring, and said second transceiveris adapted to conduct serial digital data over the second transmissionline.
 178. The device according to claim 161, wherein said firsttransceiver is operative to perform full-duplex communication with oneor more identical transceivers.
 179. The device according to claim 161,wherein said first transceiver is operative to perform full-duplexpoint-to-point communication with only a single mating transceiver overthe first transmission line.
 180. The device according to claim 161,wherein said second transceiver is operative to perform full-duplexcommunication with one or more identical transceivers.
 181. The deviceaccording to claim 161, wherein said second transceiver is operative toperform full-duplex point-to-point communication with only a singlemating transceiver over the second transmission line.
 182. The deviceaccording to claim 161, wherein communication with one of said first andsecond ports and one of said first and second transceivers,respectively, is carried out with signals that conform to an Ethernetprotocol.
 183. The device according to claim 161, wherein at least oneparameter of the device is configurable by a connected data unit. 184.The device according to claim 161, wherein the protocol of signals onthe first transmission line is different from the protocol of signals onthe second transmission line, and said device is further operative toconvert between the different protocols.
 185. A device for coupling adata unit and a powered unit to wiring composed of at least twoconductors and simultaneously carrying a bi-directional serial digitaldata signal and a power signal, said device comprising: a wiringconnector operative for connecting said device to the wiring; a dataconnector coupled to said wiring connector and connectable to a dataunit, for coupling the serial digital data signal to the data unit; apower connector coupled to said wiring connector and connectable to apowered unit, for powering the powered unit by the power signal; and asingle enclosure housing said wiring connector, said data connector andsaid power connector, wherein said enclosure is attachable to a wall andsaid device is addressable in a network.
 186. The device according toclaim 185, wherein the wiring is in the wall and is one of: atwisted-wire pair; a coaxial cable; a telephone wire pair; and powerlinewiring, and wherein said wiring connector is adapted to connect to thewiring.
 187. The device according to claim 186, wherein said singleenclosure is constructed to have at least one of the following: a formsubstantially similar to that of a standard outlet; wall mountingelements substantially similar to those of a standard wall outlet; ashape allowing direct mounting in an outlet receptacle or opening; and aform to at least in part substitute for a standard outlet.
 188. Thedevice according to claim 186, wherein the device is pluggable into andattachable to an outlet.
 189. The device according to claim 185, whereinsaid single enclosure is structured to attach to a mating fixturesecured on the wall.
 190. The device according to claim 185, furthercomprising at least one active unit, and wherein said device furthercomprises: a power supply connected to said at least one active unit forDC powering said at least one active unit, said power supply comprisingan AC/DC converter or DC/DC converter and being coupled to said wiringconnector for being powered from the power signal; and a visualindicator coupled to said power supply for indicating a status.
 191. Thedevice according to claim 185, further comprising firmware and aprocessor executing said firmware, wherein the serial digital data iscoupled to said processor via said wiring connector.
 192. The deviceaccording to claim 191, further comprising at least one user settablemanual switch coupled to said processor and actuatable by a user forassigning a device parameter.
 193. The device according to claim 192,wherein said at least one manual switch is used to manually assign anaddress to said device.
 194. The device according to claim 185, whereinsaid device has an address assigned automatically or by a data unitconnected to said device.
 195. The device according to claim 185,wherein the digital data and power signals are each carried overdistinct and dedicated wires.
 196. The device according to claim 185,wherein the digital data and power signals are multiplexed and carriedover the same conductors.
 197. The device according to claim 196,further comprising a data/power splitter having first, second and thirdports, wherein only the power signal is passed from said first port tosaid second port, and the digital data signal is passed between saidfirst and third ports.
 198. The device according to claim 197 furtherwherein said data/power splitter comprises a split-tapped transformer.199. The device according to claim 185, further comprising a transceivercoupled between said wiring connector and data connector, for conductingthe serial digital data signal over the wiring.
 200. The deviceaccording to claim 199, wherein said transceiver is operative tobi-directionally communicate with one or more identical transceiversover the wiring.
 201. The device according to claim 199, wherein saidtransceiver is operative to perform bi-directional point-to-pointcommunication with only a single mating transceiver over the wiring.202. The device according to claim 185, further comprising a transceivercoupled between said wiring connector and said data connector, saidtransceiver being operative to perform full-duplex digital datacommunication with the data unit.
 203. The device according to claim185, wherein the digital data communicated with said data unit isEthernet based.
 204. The device according to claim 185, wherein at leastone parameter of the device is configurable by a connected data unit.205. The device according to claim 185, further operative to provide astandard computer bus interface, said device further comprising acomputer connector and mechanical means for connecting and attachingsaid device to a computer plug-in unit, said computer connector beingcoupled to said wiring connector.
 206. The device according to claim205, wherein said standard computer bus interface is one of: an ISAinterface, a PCMCIA interface, an IDE interface, and a SCSI interface.207. The device according to claim 185, wherein the wiring is apowerline wiring, the power signal is an AC power signal, and said powerconnector is an AC power connector.
 208. The device according to claim185, wherein the wiring comprises at least one twisted pair and whereinthe power signal is a DC power signal.